首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3833篇
  免费   223篇
  国内免费   14篇
耳鼻咽喉   24篇
儿科学   219篇
妇产科学   53篇
基础医学   578篇
口腔科学   79篇
临床医学   282篇
内科学   710篇
皮肤病学   107篇
神经病学   203篇
特种医学   127篇
外科学   619篇
综合类   65篇
一般理论   3篇
预防医学   187篇
眼科学   100篇
药学   394篇
中国医学   15篇
肿瘤学   305篇
  2023年   20篇
  2022年   38篇
  2021年   107篇
  2020年   66篇
  2019年   80篇
  2018年   106篇
  2017年   72篇
  2016年   82篇
  2015年   97篇
  2014年   142篇
  2013年   160篇
  2012年   266篇
  2011年   258篇
  2010年   162篇
  2009年   134篇
  2008年   220篇
  2007年   223篇
  2006年   208篇
  2005年   176篇
  2004年   132篇
  2003年   163篇
  2002年   133篇
  2001年   95篇
  2000年   89篇
  1999年   104篇
  1998年   55篇
  1997年   23篇
  1996年   21篇
  1994年   14篇
  1992年   45篇
  1991年   34篇
  1990年   33篇
  1989年   45篇
  1988年   23篇
  1987年   21篇
  1986年   18篇
  1985年   25篇
  1984年   24篇
  1983年   14篇
  1980年   14篇
  1979年   22篇
  1978年   18篇
  1976年   20篇
  1975年   17篇
  1974年   17篇
  1973年   22篇
  1971年   21篇
  1970年   22篇
  1969年   23篇
  1968年   17篇
排序方式: 共有4070条查询结果,搜索用时 31 毫秒
1.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
2.
3.
INTRODUCTION: Autoimmune hepatitis (AIH) is a well-defined entity in the West but there are sparse Indian data on this disease. AIM: To study the clinical profile and response to treatment of Indian patients with AIH. METHODS: This is a part retrospective and part prospective study of 50 patients (median age 48 years, range 11-82; 43 women) seen between 1995 to 2001, diagnosed to have AIH as per the revised scoring system. Clinical and laboratory profile, response to treatment, and complications of treatment were analyzed. RESULTS: AIH accounted for 6% of all patients with liver disease seen during the period. The presenting symptoms were gastrointestinal in 43 and non-gastrointestinal in 7, with median symptom duration of 6 months (range 2 weeks to 40 years). Forty patients (80%) had chronic liver disease. Associated illnesses were present in 28 patients. Twenty-six patients were classified as definite and the rest as probable AIH. Forty-nine patients had Type 1 AIH. Five patients had overlap syndrome. Forty-five patients (90%) received immunosuppressive therapy. Twelve of 18 patients receiving only prednisolone and 21 of 27 patients receiving prednisolone and azathioprine combination responded. Thirteen (26%) patients had therapy-related complications (infectious 5, non infectious 8) with two treatment-related deaths. CONCLUSION: Type 1 AIH was the predominant type of AIH. The majority of patients with AIH presented with chronic liver disease. There was good response to immunosuppressive therapy. Therapy-related complications occurred in one-fourth of patients.  相似文献   
4.
5.
Preclinical and clinical investigations currently underway are employing novel strategies for combining vaccines with conventional and experimental anticancer therapies. To date, the FDA has not approved a therapeutic cancer vaccine. However, the results of recent investigations suggest an increasing role for vaccines in new models of combination therapy for many types of cancer. This article reviews and discusses therapeutic cancer strategies that employ vaccines in combination with local radiation, chemotherapy, hormone therapy, and anti-CTLA-4 mAb. Preclinical studies have shown that certain anticancer agents have immune modulatory effects that result in up-regulation of surface expression of MHC molecules, tumor-associated antigens, or Fas on malignant cells, rendering them more susceptible to immune destruction. Preliminary results of clinical studies using combination strategies have demonstrated a postvaccination antigen cascade, prolonged time to disease progression, and improved overall survival. Several larger randomized trials are ongoing, and more are required to support these findings.  相似文献   
6.
7.
BACKGROUND: Laparoscopic suturing and tying constitute advanced minimally invasive surgery skills. Developing proficiency in the standard methods with needle drivers is often an arduous process. Recent advances in laparoscopic instrumentations has allowed for easier methods of suturing and tying. This study investigated the hypothesis that the use of a specialized suturing device and a specialized tying device allows inexperienced medical students to suture and tie laparoscopically. METHODS: Preclinical medical students who had not received any training in open or laparoscopic surgery were included in this investigation. Each student was given a 5-minute demonstration of a specialized suturing device and a specialized tying device. The medical students were not allowed to deploy either device before actual use. After the demonstration, each student was given the device to use in a porcine model. Times were recorded and a subjective grade was given for each student. RESULTS: Twenty medical students were involved in this study. All medical students were able to complete the task of suturing and tying. The average time to suture was 104.6 seconds and the average time to tying was 31.2 seconds. The average subjective performance grade was 90 (out of 100). CONCLUSION: Specialized devices are easy to learn and use for laparoscopic suturing and tying with minimal instruction even for inexperienced medical students. Even surgeons who are not well versed in laparoscopic surgery should be able to suture and tie with certain laparoscopic instruments.  相似文献   
8.
9.
Management of cerebral hemispherectomy in children   总被引:4,自引:0,他引:4  
Surgical removal of a cerebral hemisphere may be undertaken in patients with intractable seizure disorders. Anesthetic management of such patients has not been reviewed in detail before. This study retrospectively analyzed hospital records of ten patients undergoing cerebral hemispherectomy at the Johns Hopkins Hospital between July 1983 and February 1988. Patient records were reviewed for diagnosis, physical characteristics, preoperative medications, anesthetic management, and postoperative course in the intensive care unit (ICU). Massive and sudden blood loss was a common finding in these patients, and during the intraoperative and postoperative periods, fluid resuscitation frequently was an ongoing process. In some patients, the blood loss exceeded one blood volume and was associated with coagulopathy, hypokalemia, and hypothermia. Urine output was elevated by a glucose-induced diuresis in some patients, giving misleading information as to intravascular volume status. Seizures and hemorrhage into the hemispherectomy cavity were management problems in the ICU. From this review, the authors conclude that blood loss may be marked and precipitous during surgical removal of a cerebral hemisphere. Monitoring of intra-arterial pressure and central venous pressure (CVP) is necessary for patient management during the intraoperative and postoperative periods. Intravenous (IV) access should allow rapid intravascular volume administration as it becomes necessary. Patients should remain intubated and observed closely during the immediate postoperative period due to difficulties with hemodynamic stability, seizures, and hemorrhage.  相似文献   
10.
Aniline and its halogenated derivatives are widely used as chemical intermediates. The purpose of this study was to determine the hepatotoxic and nephrotoxic potential of the 2-haloanilines. Male Fischer 344 rats (n > or = 4) were injected (i.p.) with 1.0 or 1.25 mmol/kg of: aniline (A), 2-fluoroaniline (2-FA), 2-chloroaniline (2-ClA), 2-bromoaniline (2-BrA), 2-iodoaniline (2-IA) or vehicle (0.9% saline, 2.5 ml/kg). All compounds were injected as hydrochloride salts. Renal and hepatic function was monitored 24 h after treatment. All of the 2-haloanilines induced oliguria, diminished kidney weight, tubular casts and decreased renal cortical slice accumulation of organic anions. Blood urea nitrogen (BUN) levels were increased (P < 0.05) by treatment with 1.0 or 1.25 mmol/kg of 2-FA, 2-ClA or 2-BrA. Hepatic alterations were also observed and characterized by elevated plasma ALT/GPT activity and altered morphology in the centrilobular region. The nephrotoxic and hepatotoxic potentials were similar among the 2-haloanilines but aniline was less toxic than its 2-halo derivatives. These results demonstrated that halogen substitution at the 2-position of aniline increased hepatic and renal toxicity. However, the severity of toxicity was not influenced by the nature of the halogen substituent.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号